Indicator

ABSTRACT

Disclosed is an improved indicator, which includes a scale plate having a pointer rotatably mounted thereon; an ultraviolet light source for illuminating said scale plate; and indicia arranged on the scale plate for indicating a specific value in cooperation with the pointer, each of the indicia including first and second parts, and in which the second part includes fluorescent brightener ink or paint therein so as to be illuminated when the ultraviolet light source is turned on. When the ultraviolet light source is turned on, particularly at night, the second parts of the indicia will become visible so that the visibility of the indicia is changed from the daylight condition in which the light source is turned off. Namely, an interesting design change of the indicia of the indicator can be obtained.

This application is a continuation of application Ser. No. 07/541,205, filed Jun. 22, 1990, now U.S. Pat. No. 5,130,548, which is a continuation of application Ser. No. 07/304,598, filed Feb. 1, 1989, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an indicator, and more particularly to an indicator such as a speedmeter or a tachometer used in motor vehicles, which has an ultraviolet lamp for illuminating indicia, such as scales and numerals arranged on a scale plate of the indicator, containing fluorescent brightener therein for visibility improvement.

2. Description of the Prior Art

One type of prior art indicator, such as a speedmeter or a tachometer for use in motor vehicles, includes an ultraviolet lamp for illuminating indicia, such as scales or numerals, that contain fluorescent brightener therein. In such a conventional indicator, the fluorescent brightener emits visible light when the indicia receive ultraviolet light. Therefore, the luminance of the indicia is good when the ultraviolet lamp is on, which makes the indicia especially visible in the night-time.

However, in the conventional indicator, the fluorescent brightener is simply added directly to the indicia on the scale plate. Therefore, the design of the scale plate, namely the visible arrangement of the indicia in the indicator does not change even if the ultraviolet lamp is turned on or off.

SUMMARY OF THE INVENTION

In view of the conventional indicator, this invention has been made. Accordingly, a main object of the present invention is to provide an indicator having an ultraviolet lamp for illuminating indicia containing fluorescent brightener therein, which can change the visible arrangement of the indicia depending on whether the lamp is turned on or off.

Another object of the present invention is to improve the visibility of the indicia containing fluorescent brightener therein when the ultraviolet light is turned on.

In order to achieve the above objects, the indicator of the present invention comprises: a scale plate having a pointer rotatably mounted thereon; ultraviolet light source for illuminating said scale plate; and indicia arranged on the scale plate for indicating a specific value in cooperation with the pointer, each of the indicia including first and second parts, and the second part containing fluorescent brightener therein so as to be illuminated when the ultraviolet light source is turned on.

According to the indicator having the above structure, when the ultraviolet light source is turned on, particularly at night, the second parts of the indicia will become visible, so that the visible arrangement of the indicia will change from the condition in which the light source is turned off. Namely, useful design change of the indicia of the indicator is made to occur on the scale plate.

Further, the second part of each indicia may be formed of a transparent paint containing fluorescent brightener therein so as to fade away into a ground color of the scale plate under daylight during which the ultraviolet light source is turned off. Furthermore, the first part of each indicia may be formed of ink which contains no fluorescent brightener therein and fades away into the ground color of the scale plate during night-time. According to these structures, more useful design changes of the indication of the indicator may be obtained.

The objects and advantages of the present invention, as well as the details of the preferred embodiments, will be more fully understood when taken in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of one embodiment of the indicator according to the present invention.

FIG. 2 is a cross-sectional view taken along line II--II in FIG. 1.

FIGS. 3A, 3B and 3C are explanatory drawings showing the change of visible arrangements of the indicia on the scale plate.

FIG. 4 is an enlarged view of an indicia showing a modification of the indicia of the first embodiment of the present invention.

FIG. 5 is an explanatory drawing of a second embodiment of the indicator of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, a preferred embodiment of the present invention will be described.

FIG. 1 shows indicators 1a, 1b, such as a speedmeter or a tachometer for use in motor vehicles or the like. As shown in FIG. 2, each of the indicators 1a, 1b comprises a casing 2 having a closed rear end 2a and an open front end 2b. In the casing 2, there is disposed a movement 3. On the front portion of the movement 3, there is provided a scale plate 4 which is positioned at the open front end 2b of the casing 2. On the front side of the scale plate 4, there is rotatably disposed a pointer 5. The pointer 5 is operatively connected through a shaft 6 to the movement 3. On the front open end 2b of the casing 2, there is provided a hood 7 having a substantially cylindrical shape so as to allow sight of the scale plate 4 therethrough from the outside. On the inner upper portion of the hood 7, there is provided an ultraviolet lamp accommodating section 7a. In the ultraviolet lamp accommodating section 7a, there is disposed an ultraviolet light source such as ultraviolet lamp 8 for illuminating the scale plate 4. Further, on the front side of the hood 7, there is provided a transparent front cover 9.

FIG. 3A shows the scale plate 4. The scale plate 4 is formed from a polycarbonate plate having a substantially semi-circular shape, which is formed by punching. On the front surface of the scale plate 4, a base painting made of dark color paint such as black paint is applied. The base painting forms a ground color of the scale plate 4.

On the base painting of the scale plate 4, there is provided a plurality of indicia 10, such as scales and numerals. In cooperation with the pointer 5, these indicia 10 indicate a specific value, such as the speed of the motor vehicle. The indicia 10 comprise a first indicia arrangement 11 and a second indicia arrangement 14 which is located on the outer side of the first indicia arrangement 11 concentrically.

The first indicia arrangement 11 which comprises scales 12 and numerals 13 is located on the inner side of the scale plate 4a. The indicia 12 and 13 in the first arrangement 11 are printed on the base painting with normal ink, which contains no fluorescent brightener therein, by silk-screen printing. The color of the ink used in the first indicia arrangement has a sufficient lightness and contrast with respect to the base painting, so that in the daytime the first indicia arrangement is clearly displayed as shown in FIG. 3B.

Outside the first indicia arrangement 11 on the base painting of the scale plate 4, there is provided a second indicia arrangement 14 which comprises scales 15 and numerals 16. Since the indicia in the second indicia arrangement 14 are concentrically located to those of the first indicia arrangement 11, so that each corresponding indicia in the first and second indicia arrangements 11, 14 indicate the same value to each other. The indicia in the second arrangement 14 are printed with an ink containing fluorescent brightener therein. As the fluorescent brightener, uranine, eosin, thioflavine T, rhodamine B, or the like can be used.

In this embodiment, a transparent ink or an ink having substantially the same color as that of the base painting is used as the ink for printing the indicia of the second indicia arrangement 14. Therefore, the indicia 15, 16 in the second indicia arrangement 14 are not visible in normal daylight. Namely, in the case where the ultraviolet lamp 8 is turned off, the indicia 15, 16 of the second indicia arrangement 14 fade away into the ground color of the base painting of the scale plate 4, so that as shown in FIG. 3B, only the first indicia arrangement 11 is visible on the scale plate 4.

In the case where the ultraviolet lamp 8 is turned on, such as at nighttime, the indicia 15, 16 in the second indicia arrangement 14 become visible due to the light from the ultraviolet lamp 8, so that the second indicia arrangement 14 will be visible on the scale plate 4. In this case, since the circumference of the indicator is dark, the indicia 12, 13 in the first indicia arrangement 11 fade away into the ground color of the base painting due to the loss of contrast and lightness between the ground color of the base painting and that of the indicia.

Therefore, as shown in FIG. 3C, only the indicia 15, 16 of the second indicia arrangement 14 are visibly displayed on the scale plate 4. As a result, when the ultraviolet lamp 8 is turned on, indication different from that appearing during the daytime can be obtained, whereby a useful change in the visibility of the indicator will be achieved.

In this embodiment, as shown in FIG. 4, each indicia 15, 16 in the second indicia arrangement 14 may have an edge portion 15a, 16a formed therearound. In this case, each indicia 15, 16 in the second indicia arrangement 14 is formed from an ink having a color different from that of the base painting and contains fluorescent brightener therein, and the edge portion 15a, 16a is formed from a transparent ink containing fluorescent brightener or an ink having the same color as that of the base painting and containing fluorescent brightener therein.

According to the indicator having such indicia as described above, since the edge portion 15a, 16a of each indicia 15, 16 will be visible only when the ultraviolet light source is turned on, in addition to the visibility of the indicia 15, 16 of the second indicia arrangement 14, each indicia is enlarged and becomes more clearly visible. As a result, the overall visibility of the indicia during the nighttime is improved.

FIG. 5 shows a second embodiment of the present invention. In this embodiment, on the front cover 9 of the indicator 1, indicia 20 comprising scales 21 and numerals 22 are formed by printing with a transparent ink containing fluorescent brightener therein. The position of the indicia 20 on the front cover 9 is set in such a manner that the indicia 20 on the front cover 9 correspond to those of the scale plate 4 (not shown). In this embodiment, of course, the indicia on the scale plate 4 are formed from normal ink containing no fluorescent brightener.

In this second embodiment, when the ultraviolet lamp 8 is turned on, the indicia 20 on the front cover will be displayed thereon. Therefore, according to this embodiment, three-dimensional indication can be obtained.

It must be understood that the invention is in no way limited to the above embodiments and that many changes may be brought about therein without departing from the scope of the invention as defined by the appended claims. 

What is claimed is:
 1. An indicator, comprising:a scale plate having a ground color; a pointer having a rotation axis and being rotatably disposed on said scale plate; an ultraviolet light source of illumination; first indicia means comprising an arrangement of value symbols, for indicating a specific value in cooperation with the pointer, arranged on the plate and arrayed concentrically with respect to the rotation axis of the pointer so as to enable indication of a specific value by said first indicia means, said first indicia means being visible only under the daylight condition in which the ultraviolet light source is normally turned off, and wherein the first indicia means comprises an ink having no fluorescent brightener therein and a color the visibility of which substantially merges with the ground color of said scale plate under low levels of visible light; and second indicia means comprising an arrangement of value symbols for indicating a specific value in cooperation with said pointer, spaced from said first indicia means and arrayed both concentrically thereto and with respect to said rotation axis of the pointer, wherein said second indicia means comprises a transparent ink containing fluorescent brightener which fluoresces only when exposed to ultraviolet light under conditions of low levels of visible light and the visibility of which substantially merges with the ground color of the scale plate under daylight conditions,wherein comparative arrangement of the respective indicia means is changed between the daylight condition under which only the first indicia means can be recognized and the low visible light level condition when exposed to the ultraviolet light source under which only the second indicia means can be recognized, and wherein said first and second indicia means have the same ranges of symbol values.
 2. The indicator as claimed in claim 1, wherein the second indicia means ink is essentially the same color as that of the ground color of the scale plate.
 3. The indicator as claimed in claim 2, wherein the first and second indicia means are an imprint onto the scale plate.
 4. An indicator including a scale plate having a ground color; a pointer having a rotation axis and being rotatably disposed on said scale plate; an ultraviolet light source of illumination; first indicia means comprising an arrangement of value symbols for indicating a specific value in cooperation with the pointer, arranged on said the plate and arrayed concentrically with respect to the rotation axis of the pointer so as to enable indication of a specific value by said first indicia means, said first indicia means being visible only under the daylight condition in which the ultraviolet light source is normally turned off, and wherein the first indicia means comprises an ink having no fluorescent brightener therein and a color the visibility of which substantially merges with the ground color of said scale plate under low levels of visible light; and second indicia means comprising an arrangement of value symbols for indicating a specific value in cooperation with said pointer, spaced from said first indicia means and arrayed both concentrically thereto and with respect to said rotation axis of the pointer, wherein said second indicia means comprises a transparent ink containing fluorescent brightener which fluoresces only when exposed to ultraviolet light under conditions of low levels of visible light and the visibility of which substantially merges with the ground color of the scale plate under daylight conditions, wherein comparative arrangement of the respective indicia means is changed between the daylight condition under which only the first indicia means can be recognized and the low visible light level condition when exposed to the ultraviolet light source under which only the second indicia means can be recognized, wherein said first and second indicia means have the same ranges of symbol values, and wherein the second indicia means ink is essentially the same color as that of the ground color of the scale plate, manufactured by the process comprising: imprinting the first and second indicia means ink onto the scale plate. 